CryptoTrader.Tax only needs "Read" or "View" access to import your trade history. This permission protects your accounts. Learn more about API access in this article here.
Click on the Sync Transactions button to go to your Gemini account.
After clicking the button, it will take you to the Gemini website where you can authorize CryptoTrader.Tax to import your trades.
Enter 2-Step Verification code.
Click on Allow to grant read-only access to your trading history.
After clicking Allow, it will take you back to CryptoTrader.Tax. To start the trade importer, click on the Sync Transactions button.
After the importer completes, you will see this notification telling you how many trades were imported or if your trades are all up to date. Once you see this, you may continue on to the next step.